1. Field of the Invention
The invention relates to the fabrication of an improved thin film probe for use in a multichip module (MCM) having improved test reliability and having the capability of in-situ testing and assembly.
2. Description of the Prior Art
Two of the key factors that limit the rapid growth of MCM technology have been the high cost and the availability of bare die that have the same quality and reliability as packaged devices. The present thin film probe is designed and fabricated to improve these two factors. It can economically test and characterize IC chips both in wafer form and as bare die prior to packaging. The thin film probe is able to produce Known Good Die (KGD), which is crucial to the wide adoption of advanced technology such as multichip module (MCM) and Chip on Board (COB).
In traditional MCM processes, before testing of the IC chips, all the IC chips are assembled on the substrate. If one chip fails during testing, the whole substrate is discarded. Costs are thus expensive and it takes a lot of time to replace the bad IC chips which are soldered on the substrate. Therefore, the manufacturing cost is increased in the prior processes. It is thus necessary to propose a novel probe and method of MCM fabrication to improve the test reliability and reduce the manufacturing costs of MCMs.